from passlib.context import CryptContext
from jose import JWTError, jwt
from datetime import datetime, timedelta
from typing import Optional
from fastapi import Depends, HTTPException, status
from fastapi.security import OAuth2PasswordBearer
from sqlalchemy.orm import Session
from app.database.database import get_db
from app.models.models import SysUser
from app.schemas.schemas import TokenData
import json

# 密码加密与验证
pwd_context = CryptContext(schemes=["bcrypt"], deprecated="auto")

# JWT配置
SECRET_KEY = "1234567890"  # 生产环境中需更换为安全的密钥
ALGORITHM = "HS256"
ACCESS_TOKEN_EXPIRE_MINUTES = 30

oauth2_scheme = OAuth2PasswordBearer(tokenUrl="login")

def verify_password(plain_password, hashed_password):
    return pwd_context.verify(plain_password, hashed_password)

def get_password_hash(password):
    return pwd_context.hash(password)

def create_access_token(data: dict, expires_delta: Optional[timedelta] = None):
    to_encode = data.copy()
    if expires_delta:
        expire = datetime.utcnow() + expires_delta
    else:
        expire = datetime.utcnow() + timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
    to_encode.update({"exp": expire})
    encoded_jwt = jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)
    return encoded_jwt

def get_user_by_name(db: Session, name: str):
    return db.query(SysUser).filter(SysUser.name == name).first()

async def get_current_username(token: str = Depends(oauth2_scheme)):
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        username: str = payload.get("sub")
        return username
    except JWTError:
        return None

async def get_current_user(token: str = Depends(oauth2_scheme), db: Session = Depends(get_db)):
    credentials_exception = HTTPException(
        status_code=status.HTTP_401_UNAUTHORIZED,
        detail="认证失败",
        headers={"WWW-Authenticate": "Bearer"},
    )
    try:
        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
        username: str = payload.get("sub")
        if username is None:
            raise credentials_exception
        token_data = TokenData(username=username)
    except JWTError:
        raise credentials_exception
    user = get_user_by_name(db, name=token_data.username)
    if user is None:
        raise credentials_exception
    return user

async def get_current_active_user(current_user: SysUser = Depends(get_current_user)):
    if current_user.is_active == 0:
        raise HTTPException(status_code=400, detail="用户未激活")
    return current_user

def has_access_to_menu(user: SysUser, menu_id: int):
    """检查用户是否有权限访问指定菜单"""
    # 管理员拥有所有权限
    if user.is_admin == 1:
        return True
    
    if not user.menu_json:
        return False
    
    try:
        menu_ids = json.loads(user.menu_json)
        return menu_id in menu_ids
    except:
        return False 